| The project in this thesis is one important part of scientific and technological major projects "Development of underground high reliability UPS (No:20080821-2)" established by Shanxi Jincheng Anthracite Coal Mining Group. It is aimed at solving the problems such as:the poor condition of electric power quality in coal mine, as well as the low DC power supply capacity and the unstable condition of power supply under coal mine, which could seriously affect the normal work of the electric equipment in underground coal mine. Currently, the monitoring and warning system, together with the communication equipment used in coal mine were an important guarantee for safe production in coal mines. However, the output power of traditional mining DC power supply was small and being of poor stability with large volume and very heavy, which could susceptible to fluctuations in coal mine underground AC power grid and was influenced of nonlinear and impact loads. Therefore, to develop a large capacity continuous intrinsically safe power supply has the important application value and practical significance.According to the requirements of the task book and the "coal mine safety regulations", in this thesis, the large capacity continuous intrinsically safe power supply, which was composed of the intrinsically safe switching power supply and uninterrupted power supply, was developed. This paper analyses the working principle of intrinsically safe power supply, and the control strategy and the concrete implementation method were completed. The main content was as follows:According to the actual working environment of intrinsically safe power supply under coal mine, The technical index and performance was compiled. Based on the study of paper related to the research, on condition of the understanding of the dynamic research as well as research abroad, the overall design scheme of intrinsically safe power supply was established.The topology of switching converter circuit as well as the half-bridge inverter circuit topology of the main circuit was developed. A reasonable PWM modulation strategy in the core TL494was fomulated, and the realization of the control method of double closed loop voltage and current was completed. A double protection circuit with over-current and over-power based on MAX4211was designed.Aiming at the requirements of intrinsically safe power supply and combined with PWM modulation strategy and intrinsically safe protection program, the hardware circuit of intrinsically safe switching power supplies, including input rectifier filter circuit, high frequency inverter circuit, control circuit, the output rectifier filter circuit, intrinsically safe protection circuit, were designed. The simulation and experiment was completed. It has been shown by the simulation and experiments results that circuit design is reasonable and it can meet the requirements of performance indicators.Corresponding to the design of hardware circuit, and combined with the technical indicators, AP method is used for the high frequency transformer and filter inductance parameter calculation as well as the design of magnetic components. The design and selection of the rectifier bridge was completed, and the power switch tube, the protection switch tube and energy storage element was researched. The designed components can meet the requirements and implemented functions of hardware circuit.Uninterrupted power supply hardware circuits and software program based on STM32has been developed and debugged. Hardware circuit includes the minimum system, current detecting circuit, voltage detection circuit, sampling circuit, communication circuit, etc. were developed. In RealView MDK development environment, the uninterrupted power supply part of the main program, including the sampling procedure, voltage adjustment procedure, the program of overcharge and discharge protection were compiled. The experimental test for Software and hardware was finished. The test results show that the software programming is reasonable, and the hardware circuit is stable and reliable under operation.The entire debugging has been made on the established experiment platform. The experiment for performance test of the intrinsically safe power supply was completed. The experiments of the waveform and running data about the intrinsically safe power supply were completed, and the spark test in the China Coal Research Institute of Taiyuan was finished. The experimental results show that the intrinsically safe power supply has reasonable structures and can be reliable under operating conditions. It has reached the requirement of system performance index, and has met the requirements. The system scheme is of feasibility and rationality. |
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